Preparation of trans-(2-bromovinyl) MIDA Boronate and Vinyl MIDA Boronate from the Corresponding Silanes
By: Josephine Nakhla, ChemFiles Volume 9 Article 1
Due to the instability of some boronic acids, the Burke group has developed very practical syntheses of some of the more challenging MIDA boronates. For instance, while trans-(2-bromovinyl) MIDA boronate (703478) could be prepared via bromoboration of acetylene and reaction with MIDA in the presence of base, a more convenient procedure was subsequently developed. The synthesis of trans-(2-bromovinyl) MIDA boronate is achieved via transmetalation of 1-bromo-2-trimethylsilylethylene with BBr3, followed by trapping with MIDA2-Na2+ to form the MIDA boronate (Scheme 12-(1)). This procedure also gave rise to the very useful building block, vinyl MIDA boronate (704415) (Scheme 12-(2)). Of note, the corresponding boronic acid is very unstable.1
- Uno, B. E.; Gillis, E. P.; Burke, M. D. Tetrahedron 2008, In Press.